My previous web-log entry gave you the recipe for dandelion wine. Now several winemakers personally e-mailed me with a question about this recipe. And at the same time the question rose on a winemaking forum. The writers all wanted to know why I added acid AND 10 lemons to my recipe for 25 liter. It seemed a lot acid all together.

Reason enough to dig a bit deeper into the acid in the lemon.

Winemaking is an old trade and also an old hobby. And the winemakers in the old days did not have the winemaking shops available where they could buy their ingredients. So most things were done with natural products.

Winemaking from grapes was relatively easy because a grape has all ingredients needed. However when wine was made from other fruit sometimes additions were needed.

A wine needs balance and one of the ingredients that balances it is acid. But where would you get acid. This question is easlily answerd: use lemons. That is why many old recipes require the addition of lemons.

Now the winemaking techniques have evolved and many techniques are at hand for hobby winemakers. We measure the must with a hydrometer and the aidity by titration kits. A shortage of acid is replenished by powdered citric acid that we can buy at the local homebrew shop.

But image you started a wine on saturday evening at 5 o'clock because that moring you picked a bunch of fruit that day. And then you realise that you have ran out of citric acid.The local supermarket however has evening opening and there they sell lemons. Now how many lemons would you need to replace the needed citric acid.

Or the other way round. You found a recipe you would like to try. The recipe mentiones to add 4 lemons. But you do not have lemons in stock at that moment because you forgot to buy them or because they were simply to expensive. How many powdered citric acid should you add instead of the fresh lemonjuice.

Or you want to make wine again in the traditional primitive way. Getting back to the source. And beware that there are more and more winemakers making wine in a primitive way again. So you do not want to use powdered citric acid to make your wine, no you want to use fresh lemon juice instead. So how much do you need to use.

Well here we go:

So I wanted to know how many lemons I should buy to replace a certain amount of citric acid in a recipe. But I wanted also to know the other way round: how much citric acid should I use to replace lemons in a recipe.

So up to the supermarket to buy some fresh lemons. Being there I always look around looking for winemaking ingredients. So I found some bottles with pressed lemonjuice. I take this along in my quest.

Lemons

Let me start with mentioning that there are no standard lemons. I bought a bag with 3 lemons and each weighed different. So each also had a different juice gain. The first one weighed 143 gram and gave 44 gram juice. the next one weighed 180 gram and gained 59 gram juice.

But globally we can derive from this that lemons contain 1/3 of their weight in juice. That is something we can calculate with.

Now we still do not know how much acid is in there.

So I measured 20 grams of lemon juice. I mixed it with water in a measuring beaker until I had the total volume of 1 liter.With this water I performed an acidity test (by titration) and the water had an acidity of 1,5.

Now with the second measurement I took the juice of 2 lemons.This was 118 gram juice.This 118 gram juice I poured in a beaker and added water until I had a total volume of 1 liter. Now the acidity test measured an acidity of 8.So 118 gram lemon juice in a liter water gives an acidity of 8 gram per liter. So 1 gram equals 8/118 = 0,07 gram acid.

Now if we keep the largest measurement as the most accurate we can safely say that 1 gram lemon juice contains 0,07 gram acid.

The bottles fresh pressed lemon juice

I already mentioned you can find bottles with fresh pressed lemon juice in the supermarket. This is pure lemon juice which has been filtered to obtain a clear juice. Many brands produce this juice.

A warning however must be made. The label attached to the bottle told that it was indeed pure lemon juice but for conserving purposes sulphite is added. So winemakers that have an allergy for sulphites or just do not want to use sulphites in winemaking should stay away from these bottles. But look at the labels yourself, maybe it is different at your supermarkets

The amount of sulphites in the bottle however is so low that it will not influence winemaking.

There are many brands that produce this lemon juice and prices vary enormously. The most expensive bottle has the lowest volume. So it is twice as expensive as the cheapest one. Carefully shopping pays off here.

For my measurements again I added water to 20 gram of the juice until the total volume was 1 liter. Again a titration test was made. My test now showed that 20 gram lemon juice solved in 1 liter had an acidity of 2.

So fresh lemon juice has a lower acidity as store-bough juice. This is not amazing as fresh pressed juice will have solids in it opposed to bought juice which will be pure.

So using the calculations in B and C you will be able to decide for yourself which is cheaper: fresh lemons or store bought juice.

Keep in mind that when you add lemon juice for replacing citric acid you are also introducing lemon flavors into the must. This can be an advantage or a disadvantage.

Concluding:

The here mentioned figures are only global figures. We are doing kitchen table science here and we all know the weight of lemons as well as acidity may vary per region and season. You can however globally use these figures for convenience.